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From "Tzu-Li (Gordon) Tai" <tzuli...@apache.org>
Subject Re: Kinesis connector SHARD_GETRECORDS_MAX default value
Date Sun, 23 Apr 2017 22:39:49 GMT
Thanks for filing the JIRA!

Would you also be up to open a PR to for the change? That would be very very helpful :)


On 24 April 2017 at 3:27:48 AM, Steffen Hausmann (steffen@hausmann-family.de) wrote:

Hi Gordon,  

thanks for looking into this and sorry it took me so long to file the  
issue: https://issues.apache.org/jira/browse/FLINK-6365.  

Really appreciate your contributions for the Kinesis connector!  


On 22/03/2017 20:21, Tzu-Li (Gordon) Tai wrote:  
> Hi Steffan,  
> I have to admit that I didn’t put too much thoughts in the default  
> values for the Kinesis consumer.  
> I’d say it would be reasonable to change the default values to follow  
> KCL’s settings. Could you file a JIRA for this?  
> In general, we might want to reconsider all the default values for  
> configs related to the getRecords call, i.e.  
> Cheers,  
> Gordon  
> On March 23, 2017 at 2:12:32 AM, Steffen Hausmann  
> (steffen@hausmann-family.de <mailto:steffen@hausmann-family.de>) wrote:  
>> Hi there,  
>> I recently ran into problems with a Flink job running on an EMR cluster  
>> consuming events from a Kinesis stream receiving roughly 15k  
>> event/second. Although the EMR cluster was substantially scaled and CPU  
>> utilization and system load were well below any alarming threshold, the  
>> processing of events of the stream increasingly fell behind.  
>> Eventually, it turned out that the SHARD_GETRECORDS_MAX defaults to 100  
>> which is apparently causing too much overhead when consuming events from  
>> the stream. Increasing the value to 5000, a single GetRecords call to  
>> Kinesis can retrieve up to 10k records, made the problem go away.  
>> I wonder why the default value for SHARD_GETRECORDS_MAX is chosen so low  
>> (100x less than it could be). The Kinesis Client Library defaults to  
>> 5000 and it's recommended to use this default value:  
>> http://docs.aws.amazon.com/streams/latest/dev/troubleshooting-consumers.html#consumer-app-reading-slower.
>> Thanks for the clarification!  
>> Cheers,  
>> Steffen  

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